(1) Field of the Invention
The present invention relates to a variably operated valve system for a multi-cylinder internal combustion engine and a control apparatus for the variably operated valve system which are capably of stopping valve open-or-closure operations of intake valves and exhaust valve(s) in accordance with an engine driving state.
(2) Description of Related Art
A Japanese Patent Application First Publication (tokkai) No. 2007-100585 published on Apr. 19, 2007 exemplifies a previously proposed variably operated valve system for a multi-cylinder internal combustion engine.
This variably operated valve system is provided with a valve stop (pause) mechanism which stops (pauses) a valve open-or-closure operations of each of or a pair of intake valves and each or single exhaust valve of a part of a plurality of cylinders and a body of a lash adjuster is fixed to a cylinder head by means of a switching member in a high-speed rotation driving demanding a high output of the engine. Hence, since this lash adjuster functions as a normal lash adjuster, when a rocker arm is pushed down by means of cams, one end section of a rocker arm is swung as a swing fulcrum and the other end of the rocker arm actuates the intake valves and exhaust valves respectively by predetermined lift quantities.
On the other hand, in a common use driving area demanding a low fuel consumption, the switching member is moved in the body of the lash adjuster to make the rash adjuster lost motion to stop the operations of the intake valves and exhaust valves in a part of the cylinders. Thus, a combustion drive by only the remaining cylinder(s), namely, so called, a reduced cylinder drive is performed. Consequently, the fuel consumption (or fuel efficiency) becomes improved.